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MyVisionTest News Archive

Aug 26, 2010

Meta-analysis of Avastin for diabetic macular edemaSystematic review and meta-analysis of the treatment of diabetic macular edema (DME) with intravitreal Avastin (bevacizumab, IVB) finds that IVB is an effective short-term treatment for diabetic macular edema, and that its efficacy wanes after 6 weeks.

Diabetic retinopathy is the result of microvascular retinal changes. Hyperglycemia-induced pericyte death and thickening of the basement membrane lead to incompetence of the vascular walls, with fluid leakage into the retina. As the disease progresses, diabetic retinopathy may enter an advanced (proliferative) stage. A lack of oxygen in the retina causes fragile new blood vessels to grow along the retina and in the clear, gel-like vitreous humour that fills the inside of the eye. Without timely treatment, these new blood vessels can bleed, cloud vision, and destroy the retina. There are three major treatments for diabetic retinopathy: laser photocoagulation, injection of triamcinolone into the eye and vitrectomy. The traditional treatment for proliferative diabetic retinopathy is pan-retinal photocoagulation, which involves extrensive laser photocoagulation to large areas of the retina. In severe cases of proliferative diabetic retinopathy, when there has been extensive blood vessel growth and hemmorage in the vitreous, pan-retinal photocoagulation may be augmented by vitrectomy - the surgical removal of the vitreous from the eye. Recently, there has been reports that steroids and anti-VEGF therapy are benefitial in patients with diabetic retinopathy.

This the current study, pertinent research publications were identified through systematic searches of PUBMED and Cochrane Central Register of Controlled Trials. Change in central macular thickness (CMT) in µm and best-corrected visual acuity (BCVA) in logMAR equivalents were extracted at 6, 12 and 24 weeks, and results compared between groups receiving Avastin, a combination of Avastin and steroid therapy (intravitreal triamcinolone acetonide, IVT), and macular laser photocoagulation or sham control groups.

The summary mean difference indicated a statistically significant reduction in CMT at 6 weeks when treated with Avastin compared to control. IVB treatment, however, lost significance at 12 weeks and 24 weeks. The summary mean difference in BCVA for IVB group compared to control reached significance only at 6 and 24 weeks. Combination therapy of IVB and IVT did not result in any significant reduction in CMT or gain in vision compared to treatment with IVB alone at any point in time.

The researchers conclude that IVB is an effective short-term treatment for diabetic macular edema, and that its efficacy wanes after 6 weeks. More trials exploring the therapeutic role of Avastin in DME need to be conducted to define the role of Avastin.